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14

Molecules in the outermost layers of the atmosphere are always reaching escape velocity - but there is sufficient statistical fluctuation that you will never, ever be able to demonstrate that your shout made a particular molecule escape. Let's do some math. Assuming that your sound wave is still a sound wave (rather than a shock wave) when it leaves your ...


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The nonlinear term, $\left( \mathbf{V} \cdot \nabla \right) \mathbf{V}$, determines the steepening of a wave. This can be balanced/offset by loss terms like dispersion, diffusion, viscosity, resistivity, friction, etc. If the loss term dominates over the nonlinear term, then the wave cannot steepen as there is too much damping. If the loss term balances ...


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According to the MTU webpage Speed of Sound in Air, some things to consider: if the ideal gas model is a good model for a real gas, then you can expect, for any specific gas, that there will be no pressure dependence for the speed of sound. This is because as you change the pressure of the gas, you will also change its density by the same factor. ...


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I'll just give a short outline (many caveats though): Energy in sound waves drops off as the square of the distance (a sound wave spreads out as a sphere from your mouth). If we do not take dissipation into account, you need to compare the maximum energy of your shout and divide it by $R^2$ with $R$ the distance you want to consider. Compare the kinetic ...


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I'm not an expert, but it seems to me that the it is mono-sound. Stereo means sound coming from two independent sound channels. As there is only one source, and both sounds are the same, I would consider it mono-sound. See Wiki Stereo


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Here are some topics to read about: Frequency doubling, also called second-harmonic generation as Johannes mentions. Here, you put one wave into a medium, and some fraction of it is converted to a wave with a different frequency. By carefully engineering the medium you can get quite a high conversion percentage. Other nonlinear optical processes, not just ...


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Floris, great answer. The confusion in the question is a really common one that isn't emphasized enough in teaching. Intuitive View Here's an easy way to remember this: When the speaker pushes, the air touching the speaker moves one way. When the speaker pulls, the air touching the speaker moves the other way. Put more formally, for each movement of the ...


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The shock wave from a supersonic object is a cone composed of overlapping spherical wavefronts. As individual wavefronts form, they propagates radially outward at speed $c$ (speed of sound) and have a radius $ct$. At the same time the object traveling at speed $v$ moves forward $vt$. The angle of the vertex of the of the shock wave is known as the Mach angle ...


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Typically it is the ferrite cores in inductors/transformers that resonate mechanically, or through magnetostrictive effects that produce a high pitched whine. Switching PSUs are the main culprit. It can also occur when the EM fields interact with steel components in the PSU.


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Sometimes I just have to say LM--Y: http://www.amazon.com/Prestige-Medical-131-BLK-Stereo-Stethoscope/dp/B001ULDA9Q The word "stethoscope" is a generic term for any tool that enhances detection of subcutaneous sounds. You can use a stick or metal rod, or you can use digital transducers with Bluetooth. Now, in a more general answer: you are correct that ...


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No voice sings in a "pure tone", i.e., while the voice is in tune, the sound signal is composed of various harmonic frequencies. This gives you the "color" of the voice, and that makes the two voices distinct.


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The answer to your question is yes, we can observe beat notes between two different coherent sources of light. This fact underlies almost every precision laser experiment because it allows for lock-in detection. However, there is a subtle difference from audio beatnotes. The difference is that with sound the oscillations are in the air pressure which is ...


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Due to evaporation a layer of air forms between the water droplet and the hot surface which causes the system to vibrate by letting air escape in bursts and produce sound. I suggest reading about the description of the sound that was recorded in the Leidenfrost experiment. Article: http://www.nature.com/srep/2012/121010/srep00720/full/srep00720.html Video: ...


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If you have a small diapragm moving slowly then the air will just flow around it and you won't get any appreciable pressure rise in front of the diaphragm. That means there won't be any longitudinal pressure waves (i.e. sound waves) generated normal to the diaphragm surface. If you now make the diaphragm larger the air has farther to move to get to the ...


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Although normally considered as photon interactions, any inelastic scattering process will result in the alteration of the frequency of the electromagnetic radiation. An obvious example is Compton scattering, where high energy (X-rays+) light scatters from free electrons. The scattered light has lower energy and longer wavelengths than the light incident ...


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Intensity is defined to be the average energy passing through a unit area per second. The key here is average. By defining it this way, we avoid intensity that varies with every period. The average intensity doesn't change unless the source changes it. In calculating the intensity the r.m.s. average pressure is calculated, and this is proportional to ...



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